This invention relates to a process for the separation of 2,6-dichlorobenzaldehyde from isomeric mixtures of dichlorobenzaldehydes. The product, 2,6-dichlorobenzaldehyde is useful as an intermediate in the preparation of various chemical products, and in particular as an intermediate in the preparation of herbicides, insecticides and dyestuffs.
Dichlorobenzaldehydes may be prepared by various known methods. In some methods of preparation, the product is formed as an isomeric mixture. For example, dichlorobenzaldehydes may be prepared by ring chlorination of toluene to form a mixture of dichlorotoluenes, followed by photochlorination of the mixture to form the corresponding dichlorobenzalchlorides and hydrolyzing, for example with sulfuric acid. The product is typically an isomeric mixture of 2,3-, 2,4-, 2,5-, 2,6-, and 3,4-, dichlorobenzaldehydes. It is a primary object of this invention to provide a simple and effective method for the separation of 2,6-dichlorobenzaldehyde from an isomeric mixture of dichlorobenzaldehydes.